Preparing a tibia for receiving tibial implant component of a replacement ankle

This application is a National Stage Application, filed under 35 U.S.C. 371, of International Patent Application No. PCT/US2022/011256, filed on Jan. 5, 2022, which claims priority to U.S. Provisional Patent Application No. 63/152,996, filed Feb. 24, 2021. Any and all applications for which a foreign or domestic priority claim is identified in the Application Data Sheet as filed with the present application are hereby incorporated by reference under 37 C.F.R. § 1.57.

The present disclosure relates to an ankle replacement procedure.

An ankle joint may become severely damaged and painful due to arthritis from prior ankle surgery, bone fracture, infection, osteoarthritis, post-traumatic osteoarthritis or rheumatoid arthritis, for example. Options for treating the injured ankle have included anti-inflammatory and pain medications, braces, physical therapy, amputation, joint arthrodesis, and total ankle replacement.

Current ankle joint replacement options include preparing the distal end of the tibia by drilling through the calcaneus and the talus from the bottom of the foot to access the distal end of the tibia to ream the tibial intramedullary canal. Such approaches require an additional incision in the heel. The patient's recovery time can be extended and can delay the weight-bearing time after the surgery.

A recent improved ankle joint replacement procedure involves approaching the ankle joint space with a broach from the anterior side and preparing the intramedullary canal of the tibia manually.

Disclosed is a method of preparing an intramedullary canal in a tibia for receiving a tibial implant. In some embodiments, the method comprises:

According to another aspect of the present disclosure, the method comprises:

This description of the exemplary embodiments is intended to be read in connection with the accompanying drawings, which are to be considered part of the entire written description. The drawing figures are not necessarily to scale and certain features may be shown exaggerated in scale or in somewhat schematic form in the interest of clarity and conciseness. In the description, relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate. Terms concerning attachments, coupling and the like, such as “connected” and “interconnected,” refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. When only a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. The term “operatively connected” is such an attachment, coupling or connection that allows the pertinent structures to operate as intended by virtue of that relationship. In the claims, means-plus-function clauses, if used, are intended to cover the structures described, suggested, or rendered obvious by the written description or drawings for performing the recited function, including not only structural equivalents but also equivalent structures.

Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order, nor that with any apparatus, specific orientations be required, unless specified as such. Accordingly, where a method claim does not actually recite an order to be followed by its steps, or that any apparatus claim does not actually recite an order or orientation to individual components, or it is not otherwise specifically stated in the claims or description that the steps are to be limited to a specific order, or that a specific order or orientation to components of an apparatus is not recited, it is in no way intended that an order or orientation be inferred, in any respect. This holds for any possible non-express basis for interpretation, including: matters of logic with respect to arrangement of steps, operational flow, order of components, or orientation of components; plain meaning derived from grammatical organization or punctuation, and; the number or type of embodiments described in the specification.

Referring to, an embodiment of a method for reaming a cavity in a tibia for receiving a tibial stem component of a total ankle replacement prosthesis according to the present disclosure is represented by the flowchart.are illustrations of a tibiaand a talusof an exemplary ankle joint to help with the description.

The method comprises a step (a) of forming an ankle joint spaceby resecting a portionof the distal end of a tibiaby making a box cut as shown in. If a larger ankle joint space is necessary, a superior portionof the associated taluscan also be resected at this time. (Boxin the flowchart). In some embodiments, the ankle joint spacethus formed is anteriorly accessible. In some other embodiments, the ankle joint spacecan be formed to be accessible from other direction if needed.

Next referring to, in step (b), a cavityis formed into the distal end of the tibiafor receiving a bone interface feature such as a tibial stem component(see). (Box). The cavityformed in the tibiahas a proximal endthat is closed within the tibia and an openingat the distal end of the tibia.

The cavitycan be formed using a 90° reamer tool that has an angled neck that is configured to drive a reamer bit that is oriented 90° with respect to the handle of the reamer tool. The 90° reamer tool can ream a hole into a bone in a direction that is orthogonal to the handle of the reamer tool. Such tool can be inserted into the ankle joint space, defined by the box cut shown in, and ream the cavityinto the distal end of the tibia. To aid in reaming the cavityin the desired location on the resected distal surface of the tibia, a 90° reaming alignment guide can be used. An example of such 90° reaming alignment guideis shown in.

The 90° reaming alignment guidecomprises a substantially flat bodyand a reamer guide holeprovided in the flat body. The flat body has a top surfaceA that is intended to butt up against the resected distal surface of the tibia when aligning the guide holeon the tibia. The guide holewill guide the reamer bit of the 90° reamer tool for reaming the cavity. The alignment guidefurther comprises a referencing tabthat extends orthogonal to the flat bodyand helps align the position of the guide holewith respect to the distal end of the tibia. The referencing tabhas a surfaceA that is orthogonal to the top surfaceA and forms a right angle corner with the top surfaceA as shown in. The referencing tabcomprises an alignment platenthat is threadedly engaged in a threaded hole. In use, the flat bodyof the guide is inserted into the ankle joint spacefrom anterior side and the top surfaceA of the alignment guideis placed against the resected distal surface of the tibia with the alignment platencontacting the anterior side of the distal end of the tibia. Then, the alignment of the guide holein the anterior-posterior direction with respect to the resected distal surface of the tibia can be adjusted by threading or unthreading the alignment platen. By unthreading the alignment platenso that the platenprotrudes out of the threaded hole, the platenwill push against the anterior side of the distal end of the tibia and cause the rest of the guideincluding the guide holeto move in the anterior direction. By threading the alignment plateninto the threaded hole, the guideincluding the guide holeis moved in the posterior direction.

Referring to, an alignment jig assembly, such as the example alignment jig assembly, can be used to assist in aligning the alignment guidein a proper place to ream the cavity.shows an anterior view of the alignment assemblythat is attached to the guideand the combined assembly is secured to the distal end of the tibiafrom the anterior side. The alignment assemblycomprises an Anterior-Posterior alignment rodand a Medial-Lateral (i.e. coronal-sagittal) alignment rod.

As can be seen in the anterior view in, the Anterior-Posterior alignment rodis attached to the alignment assemblyby an alignment wing. The alignment assemblyis configured so that the Anterior-Posterior alignment rodextends parallel to the longitudinal axisL of the guide holeof the guideso that the Anterior-Posterior alignment rodcan be used to align the longitudinal axisL with the tibiain the Anterior-Posterior direction. The longitudinal axisL represents the direction of reaming that would be performed using the guide holeas a guide for the 90° degree reamer tool discussed above. The alignment can be checked simply visually or with the aid of a fluoroscope. As can be seen in the medial view in, when the Anterior-Posterior alignment rodis aligned with the tibia, the longitudinal axisL of the guide holeis also aligned with the tibiain the Anterior-Posterior direction. Thus, while viewing from the medial or lateral side, the surgeon can check the Anterior-Posterior alignment of the guide holewith respect to the tibia and adjust the position of the alignment guideas necessary ensuring that the reaming through the guide holewill advance into the tibiain the direction desired by the surgeon.

Similarly, the alignment assemblyis configured so that the Medial-Lateral alignment rodextends parallel to the longitudinal axisL of the guide holeso that the Medial-Lateral alignment rodcan be used to align the longitudinal axisL with the tibial in the Medial-Lateral direction. As can be seen in the medial view in, the Medial-Lateral alignment rodextends from the aignment assemblyand is positioned above the tibiaon the anterior side of the tibia. The alignment in the Medial-Lateral direction can be checked simply visually or with the aid of a fluoroscope viewing from the anterior side as shown in. When the Medial-Lateral alignment rodis aligned with the tibia, the longitudinal axisL of the guide holeis also aligned with the tibiain the Medial-Lateral direction. Thus, while viewing from the anterior side as shown in, the surgeon can check the Medial-Lateral alignment of the guide holewith respect to the tibiaand adjust the position of the alignment guideif necessary.

Referring to, the Anterior-Posterior alignment rodis positioned to the lateral side of the tibia. The Anterior-Posterior alignment rodis also parallel to the longitudinal axis of the guide hole. When viewing under a fluoroscope from the medial side as shown in, the Anterior-Posterior alignment rodis visible through the tibia. Thus, the longitudinal axis of the guide holecan be aligned to be in a desired position within the intramedullary canal of the tibia in the Anterior-Posterior direction under a fluoroscope. Thus, using the alignment assembly, the guide holein the 90° reamer alignment guideis aligned in both the Medial-Lateral direction as well as the Anterior-Posterior direction.

Once the alignment guideis positioned with the guide holein desired alignment, the alignment guidecan be secured in place, with appropriate pins for example, and a 90° reamer is used to ream the cavitythrough the guide holeof the alignment guide from the ankle joint space.

Next, in step (c), using the alignment assembly, the position of the stem reamer guideis adjusted in Anterior-Posterior direction to align to flexible reamer's trajectory while centering in Medial-Lateral direction depending on the trajectory of the pilot cutting bitdrilling downward from the hole. (Box). This adjustment using the alignment assemblycan be performed under a fluoroscope.

Next, referring to, in step (d), a holeis formed into the tibiausing a flexible reamerfitted with a pilot cutting bitfrom a location that is proximal with respect to the cavityuntil the flexible reamerexits into the cavityat a location that is at the proximal endof the cavity. (Box).is a lateral view of a tibiashowing the arrangement where the holeis drilled on the anterior side of the tibia. The holecan be drilled in the anterior, medial, or posterior side of the tibia. The lateral side would not be feasible because of the fibula. In some embodiments, the preferred placement of the holeis on the anterior side. Drilling of the holecan be achieved with a cannulated drill guideG but it could be from straight to a curve drill guide or adjustable drill guide to control the path of the flexible reamer.

The pilot cutting bitcan be any tool bit that is suitable for forming the holeinto the tibial. Some examples of such cutting bit are a standard reamer bit, a drill bit, a broach, etc. An example of a reamer bit as the pilot cutting bitis illustrated in. The pilot reamer bitcan comprise a threaded holefor attaching to the flexible reamer.

Next, in step (e), the flexible reameris inserted further into the cavityuntil the pilot cutting bitis within the ankle joint space. (Box).

Next, referring to, in step (f), a stem reamer guideis slipped over the pilot cutting bitand inserted into the cavity's openingat the distal end of the tibia. (Box).

In some embodiments, the stem reamer guidecan be a bushing-like structure shown in. The stem reamer guidecomprises a first portionconfigured for inserting into the cavity's openingand a second portionthat is configured for receiving a tool for assisting insertion into the cavity opening. For example, the surfaceof the first portioncan be tapered to form a press fit with the cavity opening's bone surface. In some embodiments, the first portioncan be configured with any other mechanism that will help keep the stem reamer guidein place in the cavity's opening. Some examples of such mechanism are leaf spring, tabs, straight/texture, grooves, etc. The second portionextends outward radially as shown and can be configured with a grooveG for receiving the tool for assisting the insertion into the cavity. The tool can be a wrench that fits into the groove in the second portionto impact the stem reamer guideinto the cavity opening. The stem reamer guidealso comprises a guide holeextending there through for guiding a tibia stem reamer bitdisclosed herein, in the subsequent reaming procedure described herein. Multiple sizes of the stem reamer guidecan be provided in a surgical kit to accommodate different tibial stem implant sizes.

Next, in step (g), the pilot cutting bitis replaced with a tibial reamer bit(see). (box).shows the tibial reamer bitattached to the end of the flexible reamer. The tibial reamer bitis a reamer bit that is configured and adapted for reaming when pulled by the flexible reamerin the proximal direction noted by the arrow P shown in.

Next, in step (h), by pulling on the flexible reamerand, thus, the tibial reamer bitthrough the stem reamer guidein the proximal direction P, the cavityis extended in the proximal direction by reaming the intramedullary canal of the tibia. (Box).

In some embodiments, the order of the steps (d)-(f) can be different. This alternate procedural steps are illustrated by flowchartA in. In this alternate example, the steps (a′)-(c′) illustrated in boxesA-A are the same as steps (a)-(c) of flowchart. Then, (d′) the flexible reameris inserted further into the cavityuntil the pilot cutting bitis within the ankle joint space. (BoxA).

Next, in step (e′), a holeis formed into the tibiausing the flexible reamer fitted with the pilot cutting bitfrom a location that is proximal with respect to the cavityuntil the flexible reamerexits into the cavityat a location that is at the proximal endof the cavity. (BoxA).

Next, in step (f′), the flexible reameris inserted further into the cavityuntil the pilot cutting bitextends through the guide holeof the stem reamer guideand into the ankle joint space. (BoxA).

Then, the procedure is continued with the steps (g′)-(h′), (boxesA-A). that are the same as the steps (g)-(h) in flowchart.

The tibial reamer bitcomprises one or more cutting blades. As shown in the cross-sectional view in, the leading end of the tibial reamer bitcan be provided with a threaded holefor attaching to the flexible reamer. An example of a flexible reameris shown in. The flexible reamercomprises a tipthat is configured to be removably attached to a reamer bit such as the pilot cutting bitand the tibial reamer bit. In one embodiment, the tipis threaded to mate with the threaded holeof the pilot cutting bitor the threaded holeof the second reamer bit. To facilitate threaded attaching and detaching of the reamer bits,to the flexible reamer, the reamer bits are configured to be able to be turned with a tool such as a wrench or a plier. In the illustrated examples of the reamer bitsand, the reamer bits comprise flat surfaces,, respectively, so that a wrench can be used to assist in threading and unthreading the reamer bits onto the tipof the flexible reamer. The flexible reamer, in turn, comprises similar feature, such as a hex flat-sided feature near the threaded tipso that a wrench can be used to provide counter-torque when threading and unthreading the reamer bits onto the tip. The tibial reamer bitcan also comprise a holefor receiving a removal tool that can be used to detach the reamer bitfrom the flexible reamer.

Once the tibial reamer bitis attached to the end of the flexible reamer, in step (h), the proximal end of the cavityis reamed by pulling the tibial reamer bitthrough the guide holein the stem reamer guidein the proximal direction P (see) to form an extended cavity′ (see) by pulling the flexible reamerin the proximal direction P. (Box).

The extended cavity′ will be sized for receiving a tibial stem component. The flexible reamercan be pulled in the proximal direction P as far as necessary. Generally, the diameter of the extended cavity′ will be sized to match the size of the intended tibial stem component. The tibial reamer bitcan be provided in various diameter sizes to accomplish this.

Once the extended cavity′ is reamed to a desired length, a bone interface feature can be inserted into the extended cavity′. An example of a bone interface feature is a tibia stem componentof an ankle replacement prosthesis. An example of such tibia stem componentis shown in.illustrates one embodiment of a tibial portionof a total ankle prosthesis having a tibial tray revision implantcoupled thereto. The tibial portionincludes a tibia stemhaving one or more stem components,. The tibial revision implantis coupled to the bottom stem component. For example, in some embodiments, the headis inserted into a hole formed in a bottom surface of the tibia stem(not shown).

Referring to, an extenderA for tibial reamer bitis disclosed. For example, if a tibial reamer bitis 10 mm in length, and the extended cavity′ to be reamed is to be 20 mm deep from the distal surfaceof the stem reamer guide, an extenderA that is at least 10 mm long would be snapped on to the tibial reamer bit. The extenderA does not have any cutting blades because it is not necessary. The extenderA serves to lengthen the distal end of the tibial reamer bitso that as the tibial reamer bitis pulled further into the tibia through the guide holein the stem reamer guide, the extender portion of the now extended reamerwill remain within the guide holeand maintain the tibial reamer bitin a proper attitude.

The extenderA is attached to the tibial reamer bitby inserting the leading endA of the extenderA into the extension recessin the tibial reamer bit. A snap ringis provided inside the extension recessto facilitate snap-fit engagement with the extenderA. The leading endA of the extenderA comprises an annular grooveA for receiving the snap ringwhen the leading endA is inserted into the extension recess. The extender is provided with its own extension recessA and a snap ringA situated within the extension recessA to receive and engage another extenderA by a snap-fit engagement to further extend the tibial reamer bitif necessary.

To remove the extenderA from the tibial reamer bit, a removal rod or a pin is inserted through the hole(see) provided in the body of the tibial reamer bit and push the extenderA out. As can be seen in the cross-sectional view of the tibial reamer bitin, the holeintersects the blind end of the extension recess. When the extenderA is snap-fitted and fully seated in the extension recess, the leading endA of the extender is positioned within the intersection of the extension recessand the hole. When the removal rod or a pin is inserted into the holeand all the way through the reamer, along the way, the removal rod engages the chamfered edgeC of the leading endA and urges the extenderA out of the extension recess. The force is sufficient enough to overcome the holding spring force of the snap ring.

When two extendersA are snapped together, i.e., a trailing extender is snapped into the extension recessA of the leading extender, removing the trailing extender from the leading extender works the same way. A removing rod is inserted into the holeA (see) all the way through the leading extenderA and the removing rod engages the chamfered edgeC of the leading endA of the trailing extender and urge it out of the extension recessA of the leading extender.

In some embodiments, after the step (h), the disclosed method further comprises attaching a first tibial reamer bit extenderA to a distal end of the tibial reamer bitand continue reaming the extended cavity′ by pulling the flexible reamerin the proximal direction.

In some embodiments, the disclosed method can further comprise the step (i) of attaching a second tibial reamer bit extenderA to a distal end of the first reaming guide extenderA and continue reaming the proximal end of the cavityby pulling the flexible reamerin the proximal direction.

It will be understood that the foregoing description is of exemplary embodiments of this invention, and that the invention is not limited to the specific forms shown. Modifications may be made in the design and arrangement of the elements without departing from the scope of the invention.